A21 Source Multiplier/Amplifier 50 (Soma 50) - Agilent Technologies PNA Series Service Manual

PNA Series Microwave Network Analyzers
E8361A
The tune current from the A11 phase lock board splits into two paths. One path is low-pass
filtered, removing high frequency components, and goes to the YTO main coil; the other
path is highpass filtered, removing low frequency components, and goes to the YTO FM
coil. The filters are matched in stop-band response, such that one picks up where the other
leaves off.
The frequency of the PMYO is set by a voltage from a DAC set by the A6 SPAM board.
In bands 0–3, the 3.810 to 6.8 GHz output of the YTO and the 3.8 GHz output of the PMYO
are mixed to produce the 10 MHz to 3.0 GHz output frequency that is sent to the
multiplier/amplifier 20 (MA 20). In bands 4–26, the 3 to 10 GHz output of the YTO is
filtered and sent directly to the MA 20.
An additional signal is split off from the output signal and routed to the
Offset Receiver Assembly
offset mode of operation (Option 080). Refer to
(Option 080).
Multiplier/Amplifier 20 (MA 20)
The MA 20 filters, amplifies, and passes through, the 10 MHz to 10 GHz output
frequencies in bands 0–10. The signals for bands 11–26 are doubled, filtered, and
amplified. Together, these two paths produce an output frequency range of 10 MHz to
20 GHz.
This signal is sent to the A21 source multiplier/amplifier 50 (SOMA 50).
A portion of this output signal is split off and combined with other inputs in the ALC
circuitry to control the output power level.
ALC Circuitry
The following inputs are combined in the ALC circuitry to produce a signal that is sent to
the MA20 to control its output power level:
• output of the MA 20 (within the A12 source)
• temperature compensation
• slope compensation
• power level DAC
• 1V/GHz signal from the A11 phase lock board

A21 Source Multiplier/Amplifier 50 (SOMA 50)

The A21 SOMA 50 consists of three signal paths:
• In the first path, the 10 MHz to 20 GHz source signals for bands 0–14 are leveled,
amplified, and passed through to the A22 switch.
• In the second path, the 10 to 20 GHz signals for bands 15–20, and 11.8 to 17.5 GHz
signals for bands 22–26, are doubled, filtered, and amplified to produce 20 to 40 GHz
and 22.35 to 35 GHz outputs respectively. (The band 22–26 signals are again doubled in
the SOMA 70 to provide the 44.7 to 70 GHz outputs.)
Service Guide E8361-90001
where it is used to create the phase lock signal for the frequency
Frequency Offset Group Operation
Theory of Operation
Source Group Operation
A13 Frequency
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